Core-drum.



0. ONSRUD.

GORE DRUM.

APPLICATION FILED MAY 12, 1913.

Patented Mar. 17, 1914 hun am: c

hliQ.

OSCAR ONSRUD, OF CHICAGO, ILLINOIS.

CORE-DRUM.

insonne.

Specification of Letters Patent.

Patented Mar. 1'?, 1914i.

Application :tiled May 12, 1913. Serial No. 767,053.

To all fte/0m it may concern.' n

Be it known that I, @sean Unseen, a citizen of the United States of America, and a resident of Chicago, county of Cook, and Statevof Illinois, have invented certain new and useful Improvements in` CoreDrums, of which the following is a specification.

This invention relates to contractible cores employed in casting inV general, and more particularly to casting in metal cylindrical objects such as pipes.

The main objects of the invention are to provide'a core drum of improved design and which may be prepared for use and operated with comparative rapidity and with little expense and waste of material.

An illustrative embodiment of this invention is shown in the accompanying drawings, in which:

Figure 1 is a longitudinal sectional view partly broken away of a core drum constructed according to this invention. Fig. 2 is an lend view of the core drum. Fig. 3 shows details of spacing blocks employed in the construction.

It is desirable to have co-re drums so constructed that they may be contract-ed for the purpose of permitting their removal from castings, or that they may contract when the castings are cooling by pressure received from the latter.

Referring to the drawings, a sheet of metal 1 is shown by way of example in the form of a cylinder having its edges 2 and 3 overlapping to form an expansion joint, so that the cylinder may be expanded or contracted. Welded to the inner surface of the cylinder are T-bars 4 having pivotal connections 5 with a pluralityof pairs of toggle arms 6. The inner ends of the toggle arms are pivoted by bolts 8 to angle bars 9 eX- tending throughout the length of the cylinder. The bars 9 are secured together by bolts 10 passing' through the said bars and spacing blocks 11. Rigid with the angle bars 9 and spacing blocks 11`are a pair of shafts 12 and 13. rlhe shaft 12 is provided with a square head 14 by means of which the core may be rotated, for the purpose of equally distributing loam around the cylinder 1 by means of a sweep. When thus rotated the cylinder 1 is supported in a hori Zontal position by being suitably journaled at the shafts 12 and 13.

It will be seen that the shafts 12 and 13 and the angle bars 9 comprise a rigid unit which may be shifted longitudinally of the cylinder 1, while the toggles 6 swing from their pivotal connections 5 with the T-bars a. This longitudinal movement of the core bars will cause the diameter of cylinder 1 to be varied, but such movement may be prevented, when the metal is being poured, by a link or lock bar 15 pivoted to one of the toggles 6 by a pin 16, and to one of the bars 9 by a pin 17. The pin 17 is removable, thus a relative movement between the toggles 6 and core bars may be permitted or not, as desired. One or more of the bars 9 is provided with a clevis 18 to which a hook may be attached for the purpose of contracting the core and lifting it out of the mold. Pin 17 may be made of wood or other soft material easily sheared by the contraction of the core drum upon the cooling and contraction of the casting. In this way possible damage to the core or casting is pre vented upon failure to remove the core before cooling of the surrounding casting.

To guide the cylinder 1 in itsl movement when contracting or expanding, one of the T-bars 4 is spaced from the cylinder by means of spacing plate 19 which is welded to the bar 1 and to the cylinder 1. The plate 19 is of such width as to leave the space 20 between bar et and the part 2 of the cylinder opposite the bar. The edge part 3 of the cylinder lits within this space 20, and may move therein when the cylinder contracts or expands. The cylinder 1 is provided with many vents21 to allow the escape of gas when the metal is poured and cooling. In operation the cylinder 1 is first covered with a suitable adhesive loam and this loam may be built up to give varying surfaces as desired, or is equally distributed thereon by rotating the core with respect to a fixed sweep, while the core is supported in suitable bearings at the ends of shafts 12 and 13. Rotation of the core is effected by means of a suitable crank applied at the square end 14E of the shaft 12. In casting, thecore is set horizontally or upright and centered within a suitable flask or mold. The metal is then poured around the core and before the metal begins to contract, pin 17 may be removed thus allowing the cylinder l to contract and the core to be removed from the mold by a lifting or pulling means applied at the clevis 18. The outward movement of the core bars 9 first causes the toggles 6 to swing around their pivots 5, until the edge 3 of the cylinder 1 engages the filler plate 19 located between and Welded to one ofthe T-bars 4L and the cylinder 1 near its edge 2, then the entire core moves outwardly.

The present invention thus provides an extremely simple contractible core drum requiring little time or labor to prepare it for the mold and to insert and remove it to and from the mold.

Although but one specific embodiment of this invent-ion has been herein shown and described, it will be understood that numerous details of the construction shown may be altered or omitted Without departing from the spirit of this invention as defined by the following claim.

I claim:

A contractible core drum adapted to contract through pressure of a cooling surrounding casting, means normally preventing the contraction of the core drum, said means including a member adapted to make said means ineffective when a predetermined pressure is applied to the drum.

Signed at Chicago this 5th day of May OSCAR ONSRUD. Witnesses:

M. IRENE HU'rcHINGs, RUDoW RUMMLEB.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner ot Patents,

Washington, D. C. 

